Aerial vehicles such as airplanes or helicopters are commonly used to transport people or cargo from origins to destinations by air. Aerial vehicles may be formed from lightweight metals, plastics or composites and equipped with motors, rotors or other systems that are designed to meet or exceed a number of operational constraints or requirements including speed, altitude or lift. For example, many aerial vehicles (such as UAVs, or drones) are built from molded plastic frames and outfitted with electric motors powered by onboard batteries or other power sources that permit the vehicles to conduct lifting or thrusting operations, while larger aerial vehicles such as jumbo jets feature aluminum, titanium or carbon fiber frames and skins and are equipped with petroleum-powered jet engines capable of generating tens of thousands of pounds-force.
A manufactured aircraft tends to vibrate in a set of preferred modes, one or more of which may be commonly identified by an associated set of natural frequencies of vibration, or frequencies at which resonance occurs, and comparatively large-scale vibrations are observed. The discrete natural frequencies of a set that are associated with a specific aircraft necessarily depend upon structural properties (e.g., geometrical and material properties) of the aircraft. When an aircraft is built according to design specifications, the aircraft may be expected at have a known or predictable set of natural frequencies of vibration. Because an aircraft's natural frequencies of vibration depend upon its structural properties such as geometry, stiffness or damping, or the placement of individual components, each aircraft has a unique set of natural frequencies of its vibrational modes. Moreover, an aircraft's natural frequencies of vibration may change over time for any number of reasons or according to any number of factors. For example, where an aircraft's structural properties are modified due to wear and tear, damage, construction anomalies, operating histories or conditions (e.g., varying weight distributions, motor operations, or configurations of appurtenances such as landing skids), or simply due to settling of its components under vibration, displacement, stress, or forces, the set of natural frequencies of vibration of that aircraft are likewise subject to change.